The Rarest Snail in the World

First Contact

One of the intriguing things about C. nanus is its colorful and enigmatic history in the scientific literature. The snail was first described in 1888 by Charles Johnson Maynard, an eccentric zoologist and professional specimen collector. Maynard somehow persuaded a schooner captain who was sailing several hundred kilometers from Kingston, Jamaica, to Grand Cayman to let him off on Cayman Brac, the middle-sized Cayman Island. How Maynard got to Little Cayman is unrecorded, but he probably got a fisherman or turtler to take him the remaining eight kilometers.

Maynard became a Cerion specialist, although he used an older generic name, Strophia. Maynard was not only eccentric, he was also an overly enthusiastic namer of new species. In his life, he named 248 species of Cerion, 10 of which came from Little Cayman. One of these was the dwarf Strophia, S. nana, which later became Cerion nanus. Only two of his Little Cayman species, Cerion pannosum and C. nanus, are accepted by modern scientists. Maynard published his snail work in 1889 in a journal of his own invention, Contributions to Science, which was printed in very small numbers. He explained in his inaugural issue:

I have long felt the need of some organ wherein I could publish papers upon various scientific subjects, where they would be accessible. To be sure, this could be done in the journals of various natural history societies, but this procedure would defeat one of the very objects that I have in view, that of placing my work of this description in a concentrated form, where it can be had by any one who chooses to procure it, without subscribing to the publications of half a dozen societies.

Reading this, my husband and I deduced that Maynard—self-educated in science with some decidedly peculiar ideas about taxonomy—had suffered from rejections by those journals of various natural-history societies. Nonetheless, what Maynard observed about C. nanus would be irresistible to any curious natural historian. He wrote:

The island of Little Cayman is only ten miles long with an average width of two miles [sic], and is thus a mere spot in the waters of the Caribbean Sea, and the Dwarf Strophias occur in a space which is only five or six yards wide by twenty long, on this little key…. I consider that this species has the most restricted range of any animal with which I am acquainted.

Not only did Maynard conclude that C. nanus existed in a single, small population, he also found it almost exclusively on one plant species now known as Evolvulus squamosus. Also called the rockyplains dwarf morning glory, the species is patchily distributed on Little Cayman but also lives on many other Caribbean islands and in Florida. Maynard pronounced C. nanus “dwarfed to an extreme degree, from feeding on the pungent leaves of the plant described.” At only about half the length of C. pannosum, C. nanus seemed to compete with the larger, more ubiquitous snail.